This invention relates to compositions for degreasing, paint removal, coating removal, and the like. More particularly, this invention relates to compositions containing a carbonate such as alkylene carbonate or dialkyl carbonate or both, and one or more other components such as a dibasic ester and a mono-ester, or a hydrogenated hydrocarbon solvent such as a naphthene.
Paint removing compositions are commonly used in industry, such as for stripping paint from airplane fuselages. Conventional paint remover compositions include methylene chloride, phenol, or caustic. Each of these materials, however, has inherent problems during use. While methylene chloride based compositions are very effective as paint removers, methylene chloride is a highly volatile material which is considered toxic. Similarly, phenol is highly toxic. Furthermore, caustic causes burns and attacks aluminum. Due to the deficiencies and disadvantages of conventional paint removing compositions, new paint removing compositions are highly desirable.
Another area where solvents find significant commercial interest is in the area of degreasing. Degreasing compositions are well known and commonly used in industry. For example, fluorinated hydrocarbons and chlorinated hydrocarbons such as methylene chloride have been used for this purpose. However, as stated above, methylene chloride is a highly volatile material which is considered toxic. A need exists for degreasers that are neither as volatile nor as toxic as conventional degreasers such as chlorinated hydrocarbons.
The invention provides a solution to one or more of the problems and disadvantages discussed above.
This invention pertains to certain compositions useful as paint removers, and processes thereof. This invention also pertains to other compositions that are useful as degreasers, and processes thereof.
In one broad respect, this invention is a composition useful as a paint remover, comprising: a carbonate, a dibasic ester and a mono-ester. In one embodiment, the composition may also contain an organic sulfur-containing compound, a glycol ether, a ketone, or combination thereof.
In another broad respect, this invention is a process for removing paint, comprising: applying a composition to a painted surface for a time and under conditions effective to cause blistering or bubbling of the paint, wherein the composition comprises a carbonate, a dibasic ester and a mono-ester.
In another broad respect, this invention is a process for removing a coating from a surface, comprising: providing a composition containing a carbonate, a dibasic ester and a mono-ester; adding a thickening agent to the composition and mixing the resulting composition to form a thickened composition; applying the thickened composition to a coated surface for a time sufficient and under conditions effective to separate at least a portion of the coating from the surface; and removing the coating and thickened composition from the surface.
In another broad respect, this invention is a process of the manufacture of a paint stripper, comprising: combining a carbonate, a dibasic ester and a mono-ester in amount and under conditions effective to form a miscible composition. The combining of the components may be effected as by stirring, typically at the ambient atmospheric pressure and temperature. The composition may include additional components as disclosed herein.
The surfaces to be treated may be sealed with a variety of sealants, such as polysulfide, polyurethane, lacquer, epoxy, and the like. The compositions can be used to remove paints and coatings from furniture, automobiles, boats, trains, airplanes, military vehicles, and so forth.
This invention has a number of advantages. For example, the compositions have several important attributes, including low toxicity, high efficacy in removing paint and coatings. It has further been advantageously found that the compositions may be blended with additional co-solvents, activators, corrosion inhibitors, and the like, or may be used directly to effect paint removal. Furthermore, in the case of propylene carbonate, the propylene carbonate breaks down into propylene glycol, which is non-toxic. Hence, the propylene carbonate compositions of this invention are environmentally friendly, particularly as compared to chlorinated hydrocarbons and the like which are commonly used for paint and coating removing. The compositions of this invention may advantageously be of low volatility and free of carcinogenic chemicals.
In yet another broad respect, this invention is a composition useful as a degreaser, comprising: a carbonate and a alkyl-substituted cyclo-alkane such as naphthene, which is often made by hydrogenation of alkylated benzene such as toluene, xylene, ethyl benzene, ethyl toluene, and ethyl xylene, or of alkylated cyclopentene. Thus, the alkyl-substituted cyclo-alkanes used in the practice of this invention typically have one or more alkyl groups attached to a cyclopentane or cyclohexane ring. This composition may include one or more additional solvents that function as compatibilizers for carbonate and alkyl-substituted cycloalkane composition if such a compatibilizer is needed to form a miscible solution. Thus, the compatibilizers are employed in an amount effective to form a miscible solution between the carbonate and the alkyl-substituted cyclo-alkanes. In general, the alkyl-substituted cycloalkanes has up to about 30 carbons. Such additional solvents may include, for example, glycol ethers, alkyl acetates of oxo alcohols (for example, EXXATE 900, available from Exxon Chemical) such as of formula Rxe2x80x94Oxe2x80x94C(O)xe2x80x94CH3 where R is alkyl, soy carbonates, alkyl soyates, and alkyl lactates such as ethyl lactate. The base composition may also comprise a soy carbonate as the base solvent.
In another broad respect, this invention is a method useful for removing grease from a substrate, comprising: applying a degreasing composition to a grease on a substrate in an amount and under conditions effective to remove at least a portion of the grease from the substrate, wherein the composition comprises a carbonate and a alkyl-substituted cycloalkane, and optionally a soy carbonate. The composition may include a glycol ether, alkyl acetate, or other compatibilizer. As used herein, soy carbonate refers to alkyl carbonates based on soy epoxides such as the Vikoflex(trademark) epoxides currently available from Elf Atochem. Soy epoxides are based on long chain monounsaturated materials. The epoxides may be converted to carbonates by well known, catalyzed carbon dioxide insertion reactions. Since unsaturated materials from soy oil may contain both terminal and internal ethylenic functionality, the soy carbonate may have terminal functionality or may have branching.
The substrates to be treated to remove grease may be any solid surface, such as made from metal (for example, steel, aluminum, tin, copper, and so forth), glass, concrete, and wood. In most circumstances, it is preferred that the substrate is of a material that does not dissolve by action of the degreasing composition.
In another respect, this invention is a method of manufacturing a degreasing composition, comprising: combining a carbonate and a alkyl-substituted cyclo-alkane and optionally a soy carbonate. Likewise, the composition may be made by further combining the carbonate and the alkyl-substituted cyclo-alkane with a glycol ether, an alkyl acetate, or other compatibilizer. Additional components may also be combined.
This composition comprising carbonate and naphthene has a number of advantages. For example, the compositions have several important attributes, including low toxicity, high efficacy in removing grease. It has further been advantageously found that the compositions may be blended with additional co-solvents, activators, corrosion inhibitors, and the like, or may be used directly to effect degreasing. Furthermore, in the case of propylene carbonate, the propylene carbonate breaks down into propylene glycol, which is non-toxic. Hence, the propylene carbonate compositions of this invention are environmentally friendly, particularly as compared to chlorinated hydrocarbons and the like which are commonly used for removing grease. The compositions comprising carbonate and naphthene of this invention may advantageously be of low volatility and free of carcinogenic chemicals.